一株沙福芽孢杆菌的耐受性研究

为了利用沙福芽孢杆菌产纤维素酶的特性改进生物堆肥技术,对一株沙福芽孢杆菌的抗逆性进行了研究,探究了培养条件和抗生素对芽孢形成率及芽孢数量的影响。结果表明：温度37 ℃、pH=7、装液量125 ml、培养时间24 h为沙福芽孢杆菌最佳产孢条件;初始pH为7时菌液的活菌数为1.54×10⁸ cfu/ml,芽孢数为1.72×10⁸ cfu/ml,产孢率为89.5%;沙福芽孢杆菌对高浓度的赤霉素有抗性,对低浓度的硫酸链霉素、硫酸卡那霉素有抗性。     

一株产抗单增李斯特菌细菌素的枯草芽孢杆菌C3产芽孢条件的优化

枯草芽孢杆菌C3可产抗单核细胞增生李斯特菌的细菌素,有良好的抗逆性,具备开发为微生态饲料制剂的潜力。为提高该菌的芽孢数量和产孢率,对其产芽孢条件进行优化。通过单因素试验及正交试验对枯草芽孢杆菌C3的产孢培养基和培养条件进行研究。结果表明,优化后的产芽孢培养基为麸皮1.0%,花生饼粉1.0%,CaCl_2 1.0%,pH 7.5;优化后的培养条件为装液量50 m L/250 m L,接种量2.0%,摇床温度40℃,160 r/min,培养时间36 h。在优化条件下,芽孢数达41.60亿CFU/m L,产孢率为91.42%。     

枯草芽孢杆菌发酵菌糠制备饲料微生物添加剂的研究

试验旨在优化枯草芽孢杆菌发酵金针菇菌糠的条件进而制备饲料微生物添加剂。试验采用L1(645)正交试验,测定枯草芽孢杆菌发酵金针菇菌糠的培养温度(A)、外源氮水平(B)、初始pH值(C)、发酵时间(D)、菌液接种量(E)5个因素对芽孢数的影响,同时测定发酵产物的有毒、有害物质含量。结果表明,枯草芽孢杆菌的最适发酵条件为培养温度35℃、棉粕添加量3%、初始pH值7.5、发酵时间48 h、菌液接种量10%。对其发酵结果的影响程度依次是外源氮水平>初始pH值>发酵时间>接种量>培养温度。此添加剂中的黄曲霉毒素B1以及重金属砷、铅、汞、镉的含量均符合国家饲料添加剂卫生指标。在此条件下固态发酵菌糠,枯草芽孢杆菌的芽孢数为8×109cfu/g(干重),对其发酵后产品烘干即得到饲料微生物添加剂。     

纳豆芽孢杆菌增殖培养的研究

试验采用单因素法和响应面法对一株纳豆芽孢杆菌的液体发酵培养基和培养条件进行优化。最终培养基成分:蔗糖29.42 g/l、酵母粉8.13 g/l、柠檬酸钠1.0 g/l、MgSO4.7H2O 0.2 g/l、K2HPO44.0 g/l、KH2PO46.0 g/l、初始pH值7.23;最佳培养条件:装液量50 ml/250 ml、接种量3%、发酵温度40℃、转速200 r/min、发酵时间11 h,纳豆芽孢杆菌活菌数达到7.5×109cfu/ml。     

枯草芽孢杆菌BHI344培养条件的优化

以牛肉膏蛋白胨培养基为初始培养基,探讨了不同培养时间、初始pH值、温度、接种量、碳源、氮源、无机盐源对枯草芽孢杆菌BHI344生长的影响,采用正交试验法优化了培养基的组成。结果表明:菌株BHI344产最大活菌数的培养条件为初始pH值7.6、接种量5%(V/V)、培养温度35℃、培养时间16h、牛肉膏2.0%(W/V)、葡萄糖1.5%(W/V)、氯化钙0.3%(W/V);以此条件培养,BHI344的活菌数能达到2.62×109CFU/mL。     

益生菌蜡状芽孢杆菌发酵条件及培养基的优化

通过单因子试验探讨蜡状芽孢杆菌的摇瓶发酵条件(初始pH、培养温度、转速和接种量等)对生长量的影响。确定最佳培养条件为初始pH7.2,培养温度25℃,转速250r/min,接种量7%。通过单因素和正交试验确定蜡样芽孢杆菌发酵培养基的最佳配比为(W/V)可溶性淀粉3.0%、豆饼粉2.0%、磷酸氢二钾0.3%、MgSO4.7H2O0.02%和CaCl20.01%。筛选出的优化培养基活菌数为36.5×108CFU/mL。     

地衣芽孢杆菌产芽孢培养基和培养条件的优化

本研究以地衣芽孢杆菌CICC 20514为对象,芽孢数和芽孢率为目标参数,采用单因素、正交试验方法对培养基配方进行筛选,并在此配方基础上对培养条件进一步优化。结果表明：最终产芽孢发酵培养基的最佳组合为20 g/L果糖、20 g/L豆粕、5 g/L K₂HPO₄、7 g/L NaCl、0.8 g/L CaCO₃和0.8 g/L MgSO₄;产芽孢最佳培养条件为37℃,220 r/min,接种量5%,装样量20%,初始pH 6.5～7.5,发酵培养时间48 h。优化后的地衣芽孢杆菌CICC 20514培养基芽孢数及芽孢率均具有良好的稳定性,发酵液芽孢数达5.8×10⁹CFU/mL,比优化前提高了58倍。     

猪源益生菌株Bacillus velezensis Z-27产芽孢发酵条件优化

对猪源益生菌株Bacillus velezensis Z-27进行发酵条件优化试验。以芽孢产率和生物量为指标,利用单因素试验和正交试验确定了摇瓶发酵的最佳条件:玉米粉1%、豆饼粉1.5%、MnSO40.03%、NaH2PO4.2H2O 0.2%、Na2HPO4.2H2O 0.4%,初始pH值7.0,250 ml三角瓶装量50 ml,接种量2%,摇床转速220 r/min,发酵温度37℃。优化后发酵液的生物量为2.33×1010 cfu/ml,芽孢产率达96.0%,为该菌株的进一步研究和应用奠定了基础。     

1株凝结芽孢杆菌的生物学特性和产芽孢发酵条件研究

试验探索1株凝结芽孢杆菌N1的耐温性能、耐模拟胃液性能、耐胆盐性能、抗生素敏感性、溶血活性等特性,通过单因素试验和正交试验,探索该菌株最优的产芽孢发酵时间、初始pH值、接种量和温度。结果显示,该菌株具有较好的耐温性能、耐模拟胃液性能、耐胆盐性能,对庆大霉素、氯霉素、环丙沙星、红霉素、丁胺卡那、头孢唑林、氨苄西林和青霉素敏感,对复方新诺明、诺氟沙星具有耐受性,无溶血活性。在发酵24 h、初始pH值6.5、接种量5%、温度40℃的条件下,芽孢数为5.13×10^(8)CFU/mL。试验为凝结芽孢杆菌N1的生产、应用提供参考依据。     

枯草芽孢杆菌液态发酵豆粕工艺优化研究

文章以豆粕为原料,采用枯草茅孢杆菌（Bacillussubtilis）对豆粕进行液态发酵,以接种量、发酵时间、初始pH、温度为因素,水解率为指标,利用L9（3^4）正交试验对不同发酵条件进行优化,确定枯草芽孢杆菌液态发酵豆粕制备大豆肽的最佳条件。结果表明：接种量为1O％,pH值为5,40℃培养48h,豆粕的水解率达78．80％。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein